module teapo.storage.attached.webSQL {

  export function mangleDatabaseObjectName(name: string): string {

    return '='+btoa(name);

  }

  export function unmangleDatabaseObjectName(name: string): string {

    if (!name || name.charAt(0) !== '=') return null;

    try {

      return atob(name.slice(1));

    }

    catch (error) {

      return null;

    }

  }

  export function wrapSQLError(sqlError: SQLError, context: string): Error {

    if (!sqlError) return null;

    return new Error(context+' '+sqlError.message + ' [' + sqlError.code + ']');

  }

  export function listAllTables(

    transaction: SQLTransaction,

    callback: (tables: string[]) => void,

    errorCallback: (sqlError: SQLError)=>void) {

    transaction.executeSql(

      'SELECT tbl_name  from sqlite_master WHERE type=\'table\'',

      [],

      (transaction, result) => {

        var tables: string[] = [];

        for (var i = 0; i < result.rows.length; i++) {

          var row = result.rows.item(i);

          var table = row.tbl_name;

          if(!table || (table[0] !== '*' && table.charAt(0) !== '=')) continue;

          tables.push(row.tbl_name);

        }

        callback(tables);

      },

      (transaction, sqlError) => errorCallback(sqlError));

  }

   export function updateEdited(

     editedUTC: number,

     transaction: SQLTransaction,

     callback: (sqlError: SQLError) => void ) {

    transaction.executeSql(

      'INSERT OR REPLACE INTO "*metadata" VALUES(\'edited\',?)',

      [editedUTC.toString()],

      (transaction, result) => callback(null),

      (transaction, sqlError) => callback(sqlError));

  }

  export function toSqlText(text: string) {

    if (text.indexOf('\u00FF') < 0 && text.indexOf('\u0000') < 0) return text;

    return text.replace(/\u00FF/g, '\u00FFf').replace(/\u0000/g, '\u00FF0');

  }

  export function fromSqlText(sqlText: string) { 

    if (sqlText.indexOf('\u00FF') < 0 && sqlText.indexOf('\u0000') < 0) return sqlText;

    return sqlText.replace(/\u00FFf/g, '\u00FF').replace(/\u00FF0/g, '\u0000');

}